CN1622380A

CN1622380A - Energy device and method for producing the same

Info

Publication number: CN1622380A
Application number: CNA2004100973360A
Authority: CN
Inventors: 本田和义; 大石毅一郎; 美藤靖彦; 中本贵之
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2003-11-28
Filing date: 2004-11-29
Publication date: 2005-06-01
Anticipated expiration: 2024-11-29
Also published as: CN100454650C; US20050118503A1; US7816032B2

Abstract

A negative active material thin film provided on a collector layer directly or via an underlying layer has a multi-layered configuration including at least two silicon thin films containing silicon as a main component. Because of this, even when the thickness of the negative active material thin film is increased, the increase in thickness of one silicon thin film can be prevented by increasing the number of silicon thin films. Thus, the diameter of silicon particles substantially in an inverse truncated cone shape is not enlarged in the silicon thin film. Accordingly, in an energy device having a thin film mainly containing silicon as a negative active material, even when the thickness of the negative active material layer is increased to obtain a larger capacity, cycle characteristics are not degraded.

Description

Energy device and manufacture method thereof

Background of invention

1, technical field

The present invention relates to a kind of energy device and manufacture method thereof.

2, correlation technique introduction

The lithium rechargeable battery primary clustering comprises negative pole currect collecting sheet, negative active core-shell material, electrolyte, barrier film, positive electrode active materials and anode collection sheet.Lithium rechargeable battery is played an important role as the energy that is used for mobile communication equipment and various AV equipment.Along with device miniaturization and performance strengthen, continuous miniaturization of lithium rechargeable battery and energy density increase.Therefore, done a large amount of effort to improving each element that constitutes described battery.

For example, Japan Patent JP8 (1996)-78002A discloses, energy density can increase by using a kind of amorphous oxides as positive electrode active materials, and this amorphous oxides is to melt special transition metal oxide mixed-powder by the mode with heating, obtains succeeded by quick cooling.

In addition, Japan Patent JP2000-12092A discloses, by using a kind of transition metal oxide of lithium that contains as positive electrode active materials, the compound that uses a kind of silicon atoms is as negative active core-shell material, and the share of setting described positive electrode active materials strengthens battery capacity and cycle life greater than the share of described negative active core-shell material.

In addition, Japan Patent JP2002-83594A discloses, and a kind of amorphous silicon membrane is used as negative active core-shell material.Owing to used described amorphous silicon membrane, compare with the situation of using carbon, can adsorb more substantial lithium, therefore can obtain the increase of capacity.

Yet as in the situation of ion secondary battery cathode material lithium, though described amorphous silicon membrane adsorbs a large amount of lithiums, in charge/discharge process, described amorphous silicon membrane expansion and the amount of shrinking are also very big at described amorphous silicon membrane.Therefore, produced the problem that keeps cycle characteristics.Described amorphous silicon membrane can form by vacuum film formation technology, as sputter, vapor deposition or similar technology.In order to increase described capacity, the negative active core-shell material amorphous silicon membrane need thickly arrive the thickness with the positive electrode consistency of thickness.Yet when the thickness setting of described amorphous silicon membrane must be big, though described battery capacity increases, cycle characteristics was tending towards degenerating.Therefore, be difficult to make big capacity and cycle characteristics all to satisfy.

Summary of the invention

The invention solves the problems referred to above of prior art, and its objective is provides a kind of energy device, this energy device comprises that a kind of main siliceous film is used as negative active core-shell material, and satisfies big capacity and cycle characteristics simultaneously, and the method for making this energy device.

To achieve these goals, a flow collection sheet (collector) layer and directly or one deck negative active core-shell material film that provides on described afflux lamella via a bottom is provided energy device of the present invention, wherein said negative active core-shell material film has sandwich construction, comprises the two-layer at least silicon thin film that comprises silicon as main component.

In addition, the method that is used to make energy device of the present invention comprises passes through vacuum film-forming method, directly or via a bottom form the step of one deck negative active core-shell material film on described afflux lamella, the described step that wherein forms described negative active core-shell material film comprises at least two silicon deposit steps of separating in time.

By reading and understand detailed introduction below with reference to accompanying drawing, these and other advantage of the present invention is to it will be readily apparent to those skilled in the art that.

Description of drawings

Fig. 1 is the viewgraph of cross-section of schematic structure that an embodiment of a kind of device that is used to make energy device of the present invention is shown;

Fig. 2 A schematically illustrates negative active core-shell material film cross section in comparative example 1 and example 1,2 and 3 to 2D, SEM figure in this order;

Fig. 3 is the distribution diagram of element on the thickness direction of the negative active core-shell material film in example 1 of the present invention;

Fig. 4 is the distribution diagram of element on the thickness direction of the negative active core-shell material film in example 2 of the present invention;

Fig. 5 is the viewgraph of cross-section of schematic structure that another embodiment of the device that is used to make energy device of the present invention is shown;

Fig. 6 A schematically illustrates negative active core-shell material film cross section in comparative example 2 and example 4 and the example 5 to 6C, SEM figure in this order;

Fig. 7 is the distribution diagram of element on the thickness direction of the negative active core-shell material film in example 4 of the present invention;

Fig. 8 is the schematic cross-sectional view that illustrates according to the exemplary configurations of the major part of the energy device of the embodiment of the invention 2;

Fig. 9 is the schematic cross-sectional view that illustrates according to the exemplary product form of the energy device of the embodiment of the invention 2;

Figure 10 is the perspective illustration of the product form of the energy device shown in Fig. 9;

Figure 11 is the schematic cross-sectional view that illustrates according to another exemplary product form of the energy device of the embodiment of the invention 2;

Figure 12 A is the plan view that is illustrated in an example of the fuse part in the energy device of the present invention, and Figure 12 B is the viewgraph of cross-section of finding out on the direction of arrow along the line 12B-12B among Figure 12 A;

Figure 13 is the viewgraph of cross-section of schematic construction that another embodiment of a kind of device that is used to make energy device of the present invention is shown;

Figure 14 A and 14B are schematically illustrated in the cross section SEM figure in this order of the negative active core-shell material film in example 6 and the example 7.

Preferred embodiment is introduced

According to energy device of the present invention and manufacture method thereof, increase according to the thickness of described anode active material layer even work as the thickness of described anode active material layer, also can prevent the cycle characteristics degeneration.According to this structure, can realize satisfying simultaneously the energy device of big capacity and cycle characteristics.

An afflux lamella and directly or the negative active core-shell material film that provides on described afflux lamella via a bottom is provided energy device of the present invention.Described negative active core-shell material film has sandwich construction, comprises the two-layer at least silicon thin film that comprises silicon as main component.

When forming silicon thin film by vacuum film-forming method or similar approach, the common formation of silicon is down the cylindrical particle of truncated cone (inverse truncated cone) shape substantially, and thickness direction is a central axis direction.When the thickness that increases described silicon thin film when increasing battery capacity, increase substantially, and therefore its diameter increases for falling the height of described particle of circular cone shape.When the negative active core-shell material that uses described silicon thin film to be used as lithium rechargeable battery is carried out charge/discharge, lithium ion in described silicon thin film by absorption/desorption repeatedly, so silicon grain expansion repeatedly.When in described silicon thin film, occurring having the described silicon grain that increases diameter, the expansion of described silicon grain causes that the interface between described silicon thin film and the described negative pole currect collecting lamella peels off, and the stress of described silicon grain and destruction, this degenerates cycle characteristics.

According to the present invention, described negative active core-shell material film has the sandwich construction of two-layer at least silicon thin film.Therefore, increase, also can prevent the increase of one deck silicon thin film thickness by the quantity that increases silicon thin film even work as the thickness of described negative active core-shell material film.Therefore, the described silicon grain diameter in described silicon thin film is not exaggerated.Therefore, increase, also can prevent the degeneration of cycle characteristics even work as the thickness of described negative active core-shell material film.Therefore, can realize a kind of energy device that can satisfy big capacity and cycle characteristics simultaneously.

According to the present invention, " comprising silicon as main component " is meant that the atomicity percentage of silicone content is 50at% or higher.In order to increase described battery capacity, silicone content is preferably 70at% or higher, and better is 80at% or higher, and is desirably 90at% or higher most.This is because along with silicone content increases, described battery capacity increases manyly.

Preferred described silicon thin film has with thickness direction and is cylindrical particle longitudinally, and described cylindrical particle is discontinuous between described silicon thin film located adjacent one another on the thickness direction.According to this structure, can suppress to have the formation of the silicon grain that increases diameter.Therefore, even in charge/discharge process repeatedly, because the adsorption/desorption of lithium ion and expansion, peel off at the interface between described silicon thin film and the described negative pole currect collecting lamella and the stress of described silicon grain and destroying also can be suppressed when described silicon grain.Therefore, can prevent the degeneration of cycle characteristics.

Preferably between described silicon thin film located adjacent one another, there is a boundary layer.According to this structure, the cylindrical particle of clamping described boundary layer can be formed discontinuous, so that suppress to have the formation of the silicon grain that increases diameter.

Preferably in described boundary layer, there are a kind of silicon compound and elementary gas.According to this structure, the cylindrical particle of clamping described boundary layer can more positively be formed discontinuous.

Preferably, this compound is nitride or oxide.Such compound is easy to form in the forming process of described silicon thin film, and discontinuous columnar silicon particle can form really.

Perhaps, between described silicon thin film located adjacent one another, provide the atomic percent of silicone content wherein to be lower than one deck intermediate layer of 50at%.According to this structure, the described cylindrical particle of clamping described intermediate layer can form discontinuous shape, so that suppress to have the formation of the silicon grain that increases diameter.

Preferably, described intermediate layer contains lithium.According to this structure, described intermediate layer can replenish lithium ion, so that increase described battery capacity.

Preferably, described intermediate layer is discontinuous film or has island.According to this structure, ion is easy to move, thereby can strengthen cycle characteristics.

The element that a kind of fusing point is lower than the fusing point of silicon is contained in preferred described intermediate layer.According to this structure, this makes and to be easy to the intermediate layer that forms discontinuous film or have island.

Can be preferred, a part of silicon that is included in the described silicon thin film is oxide.Here the Si oxide that comprises in the above-mentioned boundary layer that provides between the described silicon thin film located adjacent one another on the thickness direction is provided used Si oxide.This means that a kind of Si oxide is included in the zone line that does not comprise the top and following boundary layer on the thickness direction.Silicone content in described silicon thin film is big, and under the big situation of battery capacity, at the expansion degree height of silicon thin film described in the charge/discharge process, this may make cycle characteristics degenerate.When described silicon thin film comprises a kind of Si oxide, because that the expansion of this Si oxide in charge/discharge process gets is little, in charge/discharge process, the expansion of described silicon thin film can be suppressed, and cycle characteristics can be enhanced.

Then, a kind of method that is used to make energy device of the present invention is the method that is used to make energy device, wherein negative active core-shell material film and positive electrode active materials film are by a nonconducting layer toward each other, comprise by vacuum film-forming method directly or via a bottom on an afflux lamella, forming the step of described negative active core-shell material film, and form described positive electrode active materials film.The step that forms described negative active core-shell material film comprises two silicon deposit steps of separating at least in time.

By repeatedly carrying out the described silicon deposit step of separating in time, form single negative active core-shell material film, on described single negative active core-shell material film, be easy to form discontinuous silicon cylindrical particle on the thickness direction.Therefore, even increase when the thickness of described negative active core-shell material film, can prevent it is the increase of size on the thickness direction of cone shape silicon grain of counter-rotating truncation basically by the number that increases described silicon deposit step.Therefore, the described silicon grain diameter in described negative active core-shell material film does not increase.Therefore, increase, also can prevent the cycle characteristics degeneration even work as the thickness of described anode active material layer.Thereby, can realize a kind of energy device that satisfies big capacity and cycle characteristics simultaneously.

Here used " vacuum film-forming method " comprises multiple vacuum film manufacturing process, as vapor deposition, sputter, chemical vapor deposition (CVD), ion plating, laser ablation, or similar technology.According to the kind of film, can select a kind of suitable film build method.Can more effectively make thin negative active core-shell material film by vacuum film-forming method can.As a result, can obtain little and thin energy device.

Preferably, in the middle of at least two silicon deposit steps, the formed silicon that contains is subjected to the surface as the silicon thin film of main component and reforms and handle.Handle owing to reform in described surface, in described anode active material layer, be easy to form and make the discontinuous boundary layer of silicon cylindrical particle.Therefore, the formation with the silicon grain that increases diameter can be suppressed.

Preferably, described surface reformation processing is the surface that gas is incorporated into described silicon thin film.Being easy to carry out such surface reformation by vacuum film-forming method handles.

Preferably, described gas contains nitrogen or oxygen is used as main component.According to this structure, the silicon grain that formed before or after surface modification treatment is easy to form discontinuous shape by a kind of simple method.

Preferably, described gas is ionized, or forms plasma.According to this structure, the silicon grain that formed before or after processing is reformed on described surface can more positively form discontinuous.

Perhaps, can in described at least two silicon deposit steps, form the atomic percent of silicone content wherein be lower than 50at% an intermediate layer.According to this structure, the cylindrical particle in the described silicon thin film that formed before or after described intermediate layer forms can form discontinuous shape, thereby the formation with the silicon grain that increases diameter can be inhibited.

Preferably, be right after described silicon deposit step, in vacuum environment, form described intermediate layer by vacuum film-forming method.Form step by carry out described silicon deposit step and described intermediate layer under the situation of not destroying vacuum environment, the absorption of described intermediate layer is enhanced and peels off preventing, thereby can prevent that described battery capacity from reducing.And, by carrying out described two steps of carrying out, can form one deck negative active core-shell material film effectively with vacuum film-forming method.

Preferably, succeeded by described silicon deposit step, in vacuum environment, form described intermediate layer by vacuum film-forming method.Form step and described silicon deposit step by carry out described intermediate layer under the situation of not destroying vacuum environment, the absorption of described intermediate layer is enhanced and peels off preventing, thereby can prevent the reduction of described battery capacity.And, by carrying out described two steps of carrying out, can form one deck negative active core-shell material film efficiently with vacuum film-forming method.

Preferably, the element that a kind of fusing point is lower than the fusing point of silicon is contained in described intermediate layer.According to this structure,, be easy to the intermediate layer that forms discontinuous film or have island by in film formed process or after the film formation, heating.By forming such intermediate layer, ion is easy to move, and this can strengthen cycle characteristics.

Preferably, the fusing point of supposing the material that is used to form described intermediate layer be Tm (℃), the temperature that film forms the surface in the forming process of described intermediate layer remain on Tm/3 (℃) or higher.According to this structure, can form discontinuous film effectively or have the intermediate layer of island.

Perhaps, after described intermediate layer formed, described intermediate layer can be heated to the temperature that is equal to or higher than its fusing point.According to this structure, also can easily form discontinuous film or have the intermediate layer of island.

Preferably, described silicon deposit step is carried out in inert gas or blanket of nitrogen.According to this structure, can prevent to gather and grow and increase the situation of silicon grain diameter being parallel to silicon cylindrical particle located adjacent one another on the direction of deposition surface.Therefore, described cycle characteristics is owing to the degeneration that the silicon grain excessive expansion/contraction causes in charge/discharge process can be inhibited.As for described environmental gas, with regard to the conspicuousness of practicality and above-mentioned effect, argon gas is most preferred.

Hereinafter, will introduce embodiments of the invention with reference to the accompanying drawings.

Embodiment 1

Introduce a kind of energy device below according to the embodiment of the invention 1.

Embodiment 1 described energy device has following structure.A cylindric coiling main body is placed in the battery case, and be marked with electrolytic solution in this battery case, in this cylindric coiling main body, be wound with the anode collection sheet that is formed with positive electrode active materials on its two sides, as the barrier film of a non-conductive layer, and the negative pole currect collecting sheet quilt that is formed with negative active core-shell material on its two sides, make described barrier film be placed in the middle of described anode collection sheet and the described negative pole currect collecting sheet.

As for described anode collection sheet, can use (thickness: 10 to 80um) such as the paper tinsel made by Al, Cu, Ni or stainless steel, nets.Perhaps, also can use to be formed with metallic film on it, by PETG (polyethylene terephthalate), polymer substrate that polyethylene naphthalenedicarboxylate (polyethylene naphthalate) etc. is made.

Require described positive electrode active materials that lithium ion is entered wherein or from wherein leaving, and can form by the transition metal oxide that contains lithium, this transition metal oxide contains the transition metal such as Co, Ni, Mo, Ti, Mn, V etc., or a kind of slurry of mixing, at the transition metal oxide that contains lithium described in the described mixed slurry with such as the conductive auxiliary agent of acetylene black, and mix such as a kind of adhesive of acrylonitrile-butadiene rubber, butyl rubber, polytetrafluoroethylene, polyvinylidene fluoride etc.

As for described negative pole currect collecting sheet, can use (thickness: 10 to 80um) such as the paper tinsel made by Cu, Ni or stainless steel, nets.Perhaps, also can use to be formed with metallic film on it polymer substrate of making by PETG, polyethylene naphthalenedicarboxylate etc.

Described barrier film preferably has excellent mechanical intensity and ion penetration, and can be made by polyethylene, polypropylene, polyvinylidene fluoride etc.The bore dia of described barrier film for example is 0.01 to 10um, and its thickness is for example 5 to arrive 200um.

As described electrolytic solution, can use a kind of by will be such as LiPF ₆, LiBF ₄, LiClO ₄Deng electrolyte dissolution in such as the solvent of ethylene carbonate (ethylene carbonate), propene carbonate, carbonic acid Methylethyl ester (methyl ethyl carbonate), hexafluoro methyl acetate (methyl acetate hexafluoride), oxolane etc. and the solution that obtains.

As described battery case,,, also can adopt a kind of plastic material according to the use of battery though can use metal material such as stainless steel, iron, aluminium, nickel-plated steel etc.

Described negative active core-shell material is a kind of silicon thin film that comprises silicon as main component.This silicon thin film preferably amorphous or crystallite, and can pass through vacuum film-forming method, form as sputter, vapor deposition or CVD.

Example 1-3 and ratio change example 1

To introduce example below corresponding to embodiment 1.

At first, a kind of method that is used to make anode electrode will be introduced.Li ₂CO ₃And CoCO ₃With a predetermined mixed in molar ratio, and obtain LiCoO by adding thermal synthesis under 900 ℃ in air ₂LiCoO ₂Be sized to 100 orders or lower to obtain positive electrode active materials.Then, the described positive electrode active materials of 100 grams, 10 grams mix to obtain a kind of slurry as the polytetrafluoroethyldispersions dispersions (dispersion) and the pure water of adhesive as carbon dust, 8 grams of conductive agent.The described slurry that contains described positive electrode active materials is applied to two surfaces as the banded aluminium foil of anode collection sheet, and (thickness: 15um), oven dry obtains an anode electrode thus then.

Use banded Copper Foil (thickness: 30um) be used as the negative pole currect collecting sheet, use the method for sputter to form one deck silicon thin film on two surfaces of described Copper Foil.This will be described in detail below.

As barrier film, adopted the banded porous polyethylene (thickness: 25um) of width greater than the width of described anode collection sheet and described negative pole currect collecting sheet.

Be fixed on the described anode collection sheet by spot welding by the positive wire made from the identical materials of described anode collection sheet.And, be fixed on the described negative pole currect collecting sheet by spot welding by the negative wire made from the identical materials of described negative pole currect collecting sheet.

The described anode electrode of Huo Deing, described negative electrode and described barrier film are stacked as mentioned above, described barrier film is disposed between described anode electrode and the negative electrode, and is wound into helical form.Upper and lower surface in the described cylindric coiling main body that obtains thus provides an insulating trip of being made by polypropylene, and final cylindric coiling main body is disposed in the cylindrical battery shell at the end.Near an opening of described battery case, form a projection (stepped) part.Then, as non-aqueous electrolytic solution, Rong Xie LiPF wherein ₆Concentration is 1 * 10 ³Mol/m ³The ethylene carbonate and the diethyl carbonate solution of mixed in equal amounts, be injected in the described battery case, and with the sealing together described opening of sealing to obtain lithium rechargeable battery.

Introduce a kind of method that is used to form as the silicon thin film of described negative active core-shell material with reference to Fig. 1.

The vacuum film formation apparatus 10 that is shown among Fig. 1 comprises a vacuum tank 1, and described vacuum tank 1 is divided into the upper and lower by a partition wall 1a.Be arranged in chamber (delivery chamber) 1b of described partition wall 1a upside, providing unwinding roller 11, cylindrical shell roller 13, coiling (take-up) roller 14 and conveying roller 12a, 12b.At the chamber that is arranged in described partition wall 1a downside (film formation chamber) 1c, be furnished with the first spatter film forming source 51, gas introducing spout 55 and the second spatter film forming source 52.At the center of described partition wall 1a, a mask plate 4 is provided, and passes through the opening of described mask plate 4, the lower surface of described shell roller 13 is exposed to the side that described film forms chamber 1c.By vacuum pump 16, the inside of described vacuum tank 1 remains on a predetermined vacuum degree.

The banded negative pole currect collecting sheet 5 of described unwinding roller 11 unwindings is carried by described conveying roller 12a, described shell roller 13 and described conveying roller 12b in succession, and reels around described take up roll 14.In this process, such as the particle (hereinafter being called " sputter particles ") of atom, molecule or the cluster that produces from the described first spatter film forming source 51 and the described second spatter film forming source 52 mask plate 4 by described partition wall 1a, and be adsorbed onto on the surface of the described negative pole currect collecting sheet 5 of reeling on the described shell roller 13, thereby form film 6.Arrange that the described first spatter film forming source 51, described gas introduce spout 55 and the described second spatter film forming source 52, so that relative with described negative pole currect collecting sheet 5 from the upstream side on the direction of transfer of described negative pole currect collecting sheet 5 to the downstream.Described gas is introduced spout 55 and is extended on the whole width of (on the direction perpendicular to the picture surface of Fig. 1) on the Width of the contiguous described negative pole currect collecting sheet 5 of described shell roller 13.Thereby described gas is introduced spout 55 as second mask plate, and prevents that described sputter particles is deposited to described gas and introduce on the zone of outer surface of the relative described shell roller 13 of spout 55.Therefore, at first, described sputter particles from the described first spatter film forming source 51 mainly is deposited on the surface of described negative pole currect collecting sheet 5, and after one section short time period, mainly is deposited on the described negative pole currect collecting sheet 5 from the described sputter particles in the described second spatter film forming source 52.

In example 1, use said apparatus, come silicon in described first spatter film forming source 51 of sputter and the described second spatter film forming source 52 with argon ion, on as the Copper Foil of described negative pole currect collecting sheet 5, form one deck silicon thin film (thickness: 8um) thus.The deposition rate of described silicon thin film is set to about 2nm/s.Sputtering source as described first spatter film forming source 51 and the described second spatter film forming source 52 has adopted the magnetically controlled DC sputtering source.In the film forming process, do not introduce spout 55 and introduce gas by described gas.

In example 2, except in the film forming process, nitrogen is with 0.05Pam ³The speed of/s is introduced outside spout 55 introduces from described gas, with example 1 in identical mode form silicon thin film.

In example 3, except in the film forming process, oxygen is with 0.05Pam ³The speed of/s is introduced outside spout 55 introduces from described gas, with example 1 in identical mode form silicon thin film.

In comparative example 1, except only using the described first spatter film forming source 51, removing described second spatter film forming source 52 and described gas simultaneously introduces outside the spout 55, with with example 1 in identical mode form silicon thin film (thickness: 8um), and adjust the translational speed of described negative pole currect collecting sheet 5 so that deposition rate is the same with deposition rate in the example 1.

Fig. 2 A presses the SEM figure of this order to the cross section that 2D is schematically illustrated on the thickness direction of silicon thin film (negative active core-shell material film) described in comparative example 1 and example 1,2 and 3.In every width of cloth figure, scheme surperficial bottom side corresponding to described negative pole currect collecting sheet (Copper Foil) 5 those sides, and its upside is corresponding to the surface of described silicon thin film.

In comparative example 1 (Fig. 2 A), silicon grain grows into basic for falling the cylindrical pellet of frustum-like shape, and particle diameter increases gradually from the interface between described silicon thin film and the described negative pole currect collecting sheet, and described particle diameter is maximum near described silicon thin film.

On the contrary, in example 1 to 3 (being shown in Fig. 2 B in this order to 2D), though silicon grain grows into the basic cone shape cylindrical pellet in counter-rotating truncation ground that is similarly, on thickness direction, at core, the growth of described silicon grain is discontinuous.The described discontinuity of silicon grain growth is more remarkable in example 2 and example 3 (being shown in Fig. 2 C and 2D), has introduced gas in example 2 and example 3.The discontinuous part of described silicon grain matches each other in any described silicon grain substantially in the position on the thickness direction.In example 3, described silicon thin film is divided with the corresponding boundary layer 50 of described discontinuous part by one, and has two-layer structure in vertical direction in example 1.Layer in described boundary layer 50 bottom sides (Copper Foil side) mainly is considered to the silicon thin film that formed by the described first spatter film forming source 51, and at the silicon thin film that forms by described second sputtering source 52 of layer mainly being considered to of described boundary layer 50 upsides.Described silicon grain in described boundary layer 50 upper layer begins growth with counter-rotating truncated cones shape from described boundary layer 50 substantially.Therefore, the described particle diameter in described silicon film surface adjacent domain is littler than the particle diameter in the comparative example 1.In example 1 each silicon thin film in example 3 and the comparative example 1, measured by X-ray diffraction corresponding to a remarkable peak of silicon crystal that (CuK α 40kV) detects, so these silicon thin films are considered to amorphous or crystallite.

Fig. 3 illustrates the Auger depth section of the silicon thin film described in the example 1 (negative active core-shell material film).Described Auger depth section is to measure with the SAM 670 that Philips company produces.Described Auger depth section is that electron gun accelerating voltage, the irradiation electric current at 10kV is 10hA, the accelerating voltage that is used for etched ion gun is 3kV, and sputter rate is to measure under the condition of 0.4nm/s." apart from the degree of depth on film surface " represented by trunnion axis among Fig. 3 is to obtain by the etch depth that uses a kind of sputter rate that sputter etching time of sample is converted on the thickness direction, and described sputter rate is to obtain by the level error of measuring sputter etching silicon fiml identical with the film of described sample and copper film formation with a kind of level error measurement mechanism.As from understanding Fig. 3, in the film forming process, do not introduce in the example 1 of gas, corresponding to a position sensing of described boundary layer to one of argon gas faint peak, and do not recognize the discontinuity of tangible composition.The fact that recognizes the discontinuity of germination in Fig. 2 B is pointed out as drawing a conclusion: even the adsorbed gas of pettiness ground, its degree is surveyed less than maybe detecting faint amount with described Auger depth section, and it is discontinuous that the growth of silicon grain also can become.

Fig. 4 is the view that the Auger depth section of the silicon thin film described in the example 2 (negative active core-shell material film) is shown.As from understanding Fig. 4, in example 2, wherein said silicon thin film is exposed in the nitrogen being formed the process of film by the described first spatter film forming source 51 and formed by the described second spatter film forming source 52 between the process of film, corresponding to a position sensing of this boundary layer to the nitrogen-atoms distribution of peaks.That is to say, in described boundary layer, have a kind of nitride of silicon.Example 2 points out, when forming a kind of nitride of silicon in the forming process of described silicon thin film, the growth of the silicon grain discontinuous possibility that becomes increases.

Though do not illustrate, be exposed in the oxygen atmosphere even forming the process of film by the described first spatter film forming source 51 and forming by the described second spatter film forming source 52 between the process of film at example 3 described silicon thin films (negative active core-shell material film), with with Fig. 4 in identical mode, corresponding to a position sensing of described boundary layer to the oxygen atom distribution of peaks.That is to say, in described boundary layer, have a kind of oxide of silicon.Understand that from example 3 even form a kind of oxide of silicon in described silicon thin film forming process, the growth of the silicon grain discontinuous possibility that becomes increases.

Probe temperature, charge/discharge current that the described lithium rechargeable battery that forms in example 1 to 3 and comparative example 1 stands at 20 ℃ are 3mA/cm ², the charge/discharge cycle test that is 4.2V under the condition of 2.5V of charging scope.The discharge capacity of acquisition after 50 circulations and 200 circulations is used as the conservation rate (cycle characteristics) of battery capacity with respect to the ratio of initial discharge capacity.Table 1 illustrates this result.

Table 1

	Example 1	Example 2	Example 3	Comparative example 1
	Example 1	Example 2	Example 3	Comparative example 1	After 50 circulations	????96％	????98％	????98％	????82％
After 200 circulations	????82％	????86％	????87％	????60％	After 50 circulations	????96％	????98％	????98％	????82％

As understanding from table 1, in example 1 in example 3, wherein silicon grain to be grown on the described boundary layer of the center that is located substantially on thickness direction be discontinuous, described battery capacity conservation rate after 50 circulations and 200 circulations is than the conservation rate height in the comparative example 1, in described comparative example 1, do not have described boundary layer, and silicon grain to be grown in the gamut on the thickness direction be continuous.And, as forming the process of films in the described first spatter film forming source 51 and forming the result of introducing gas between the process of film by the described second spatter film forming source 52, the more significant example 2 of discontinuity and the example 3 of silicon grain growth, compare with the example 1 of not introducing gas, have the satisfied battery capacity conservation rate of people more in addition.

Described battery capacity conservation rate (cycle characteristics) is owing to the reason that the described discontinuity of silicon grain increases is considered to following reason.As mentioned above, in the described silicon thin film that is formed by vacuum film-forming method, silicon forms the cylindrical particle that is down frustum-like shape basically, and its thickness direction is a central axis direction.When described silicon thin film is used as the described negative active core-shell material that is used for lithium rechargeable battery, owing to charge/discharge repeats the adsorption/desorption of lithium ion, and silicon grain expansion repeatedly.This causes the destruction of peeling off of interface between described silicon thin film and described negative pole currect collecting lamella and stress and silicon grain, therefore reduces battery capacity conservation rate (cycle characteristics).When the thickness that increases described silicon thin film when increasing battery capacity, the reason that described cycle characteristics reduces is considered to as follows: silicon grain is grown according to the increase of thickness, and its maximum diameter also increases, thus the interference in the described silicon grain increases.When making the discontinuous described boundary layer of growth of silicon grain form in described silicon thin film, to example 3, described silicon grain begins growth from described boundary layer as example 1.Therefore, the increase of the maximum gauge of described silicon grain is suppressed, and the interference between the silicon grain is suppressed.Therefore, obtained the satisfied battery capacity conservation rate of people in addition.

As mentioned above, make the discontinuous boundary layer of described silicon cylindrical particle shape, can obtain to comprise the two-layer at least multilayer silicon thin film that contains silicon as the silicon thin film of main component by in described silicon thin film, forming one.Be used as the described anode active material layer that is used for lithium rechargeable battery at such multilayer silicon thin film, increase even work as the whole thickness of described anode active material layer, cycle characteristics can not degenerated yet.Therefore, the energy device that can provide a kind of raising that makes battery capacity and cycle characteristics to satisfy.

By introducing the gas ionization that spout 55 is introduced from described gas, perhaps it is formed plasma, the reactivity between gas of being introduced and the described film particles increases, and can strengthen the effect that gas is introduced.The ionization of the gas of being introduced can additionally provide the function of ion source or plasma source to realize by introducing spout 55 for described gas.As for described ion source, can adopt such as hot cathode type, hollow cathode type and similar all kinds, and type is not had particular restriction.When introducing carrier of oxygen, preferred, for example use the mist of oxygen and inert gas, so that can be because of oxidation and similarly former thereby hot cathode is degenerated.The voltage that being used to of being applied produces plasma can be any in dc voltage, AC voltage and the high frequency voltage.Even be ionized or form at the gas of being introduced under the situation of plasma, at described cross section SEM shape, described Auger depth section, with obtain on the described battery capacity conservation rate (cycle characteristics) with example 2 and example 3 in identical effect, yet, compare with example 3 with example 2, after 200 circulations, described capability retention increases about 2%.Its reason is thought as follows: when the gas of being introduced is ionized or forms plasma, the reactivity between gas of being introduced and the described film particles increases, and thus, the influence that gas is introduced the growth discontinuity that makes silicon grain strengthens.

Example 4 and example 5 and comparative example 2

With other example of introducing corresponding to embodiment 1.

At first, a kind of method of making anode electrode will be introduced.With a predetermined mixed in molar ratio Li ₂CO ₃And CoCO ₃, and by in air 900 ℃ add thermal synthesis and obtain LiCoO ₂LiCoO ₂Be sized to 100 orders or lower to obtain positive electrode active materials.Then, the described positive electrode active materials of 100 grams, 12 grams are mixed to obtain a kind of slurry as the polytetrafluoroethyldispersions dispersions and the pure water of adhesive as carbon dust, 10 grams of conductive agent.The described slurry that contains described positive electrode active materials is applied to two surfaces as the banded aluminium foil of anode collection sheet, and (thickness: 25um), oven dry obtains an anode electrode thus then.

With banded Copper Foil (thickness:, on two surfaces of described negative pole currect collecting sheet, form silicon thin film as negative active core-shell material by the vacuum vapor deposition 20um) as the negative pole currect collecting sheet.This will introduce in detail.

As for described barrier film, adopt the banded porous polyethylene (thickness: 35um) of width greater than the width of described anode collection sheet and described negative pole currect collecting sheet.

As anode electrode as described in the above-mentioned acquisition, as described in negative electrode and as described in barrier film stacked, thereby described barrier film is disposed between described anode electrode and the negative electrode, and is wound into helical form.Upper and lower surface in the described cylindric coiling main body that obtains thus provides an insulating trip of being made by polypropylene, and thus obtained final cylindric coiling main body is arranged in the cylindrical battery shell at the end.Near an opening of described battery case, form a jut.Then, as for non-aqueous electrolytic solution, Rong Xie LiPF wherein ₆Concentration is 1 * 10 ³Mol/m ³Ethylene carbonate and the mixed in equal amounts solution of diethyl carbonate be injected in the described battery case, and with the sealing together described opening of sealing to obtain lithium rechargeable battery.

Introduce a kind of method that is used to form as the silicon thin film of described negative active core-shell material with reference to Fig. 5.

The device that is shown among Fig. 5 is with the difference that is shown in the device among Fig. 1, form the layout first vapor deposition source 61, vapor deposition source, intermediate layer 65 among the chamber 1c at described film, replace the described first spatter film forming source 51, described gas introducing spout 55 and the described second spatter film forming source 52 with the second vapor deposition source 62.In Fig. 5, represent with identical Ref. No. with assembly identical among Fig. 1, and omit its explanation.

Transmit by described conveying roller 12a, described shell roller 13 and described conveying roller 12b in succession from the described banded negative pole currect collecting sheet 5 of described unwinding roller 11 unwindings, and reel around described take up roll 14.In this process, such as atom, molecule or from the described first vapor deposition source 61, vapor deposition source, described intermediate layer 65, the particle (hereinafter being called " evaporating particle ") of the cluster that produces with the described second vapor deposition source 62 is by the mask plate 4 of described partition wall 1a, and be attached on the surface of the described negative pole currect collecting sheet 5 that licks described shell roller 13, thereby form described film 6.Arrange the described first vapor deposition source 61, vapor deposition source 65, described intermediate layer and the described second vapor deposition source 62, so that they are relative with described negative pole currect collecting sheet 5 from the upstream side of the throughput direction of described negative pole currect collecting sheet 5 to the downstream.Vapor deposition source, described intermediate layer 65 is extending across the whole width of described negative pole currect collecting sheet 5 in (on the direction perpendicular to the picture surface of Fig. 5) on the Width of described negative pole currect collecting sheet 5 near the described shell roller 13.Therefore, the plate plate is covered as second in vapor deposition source, described intermediate layer 65, and prevents to be deposited on the zone of outer surface of the described shell roller 13 relative with vapor deposition source, described intermediate layer 65 from the particle of described first vapor deposition source 61 and the described second vapor deposition source, 62 evaporations.Therefore, at first, mainly be deposited on the surface of described negative pole currect collecting sheet 5 from the described evaporating particle in the described first vapor deposition source 61; Then, thereon from the main deposit of described evaporating particle in vapor deposition source, described intermediate layer 65; And in the end, thereon from the main deposit of described evaporating particle in the described second vapor deposition source 62.

In example 4 and example 5, use said apparatus, from described first vapor deposition source 61 and the described second vapor deposition source 62 deposit silicon, thus, on as the Copper Foil of described negative pole currect collecting sheet 5, form one deck silicon thin film (thickness: 6um) by the electron beam vapor deposition.The deposition rate of described silicon thin film is set to about 0.1um/s.As for described first vapor deposition source 61 and the described second vapor deposition source 62,270 ° of deflection type electron beam vapor deposition sources have been adopted.

And, in example 4, from vapor deposition source, described intermediate layer 65 vapor deposition aluminium.It is identical with the deposit amount of a vapor deposition aluminium when forming the thick film of 0.1um that the deposit amount of aluminium is set to.

And, in example 5, from vapor deposition source, described intermediate layer 65 vapor deposition lithiums.It is identical with the deposit amount of a vapor deposition lithium when forming the thick film of 0.1um that the deposit amount of lithium is set to.

In comparative example 2, except only using the described first vapor deposition source 61, and remove outside described second vapor deposition source 62 and the vapor deposition source, described intermediate layer 65, with with example 4 and example 5 in identical mode form one deck silicon thin film (thickness: 6um), and regulate the translational speed of described negative pole currect collecting sheet 5 so that described deposition rate is identical with deposition rate in example 4 and the example 5.

Fig. 6 A schematically illustrates comparative example 2 to 6C, and the SEM figure in this order of the cross section on the described silicon thin film in example 4 and the example 5 (negative active core-shell material film) thickness direction.In every width of cloth figure, the bottom side on figure surface is corresponding to described negative pole currect collecting sheet (Copper Foil) 5 one sides, and its top side is corresponding to the surface of described silicon thin film.

In comparative example 2 (Fig. 6 A), silicon grain is grown to the cylindrical particle that is down frustum-like shape substantially, and particle diameter increases gradually from the interface between described silicon thin film and the described negative pole currect collecting sheet, and in the near surface of described negative active core-shell material, described particle diameter maximum.

On the contrary, in example 4 and example 5 (being shown in Fig. 6 B and 6C in proper order) with this, though silicon grain grows into the cylindrical particle that is down frustum-like shape substantially similarly, but the both sides that are grown in layer (intermediate layer) 60 of silicon grain all are discontinuous, and the core of described layer 60 on thickness direction has thickness a little.Described silicon thin film is divided by described intermediate layer 60, and has double-layer structure in vertical direction.From described intermediate layer 60 to be considered to mainly be the silicon thin film that is formed by the described first vapor deposition source 61 than the layer of downside (Copper Foil side), it mainly is aluminium film (example 4) or the lithium film (example 5) that is formed by vapor deposition source, described intermediate layer 65 that described intermediate layer 60 is considered to, and to be considered to mainly be the silicon thin film that is formed by the described second vapor deposition source 62 at the layer of described intermediate layer 60 upsides.Silicon grain in the layer of described intermediate layer 60 upsides from the described intermediate layer 60 to be down that substantially frustum-like shape begins to grow.Therefore, near the described particle diameter described silicon film surface is littler than the particle diameter in the comparative example 2.In each silicon thin film of example 4 and example 5 and comparative example 2, measure by X-ray diffraction that (CuK α 40kV) does not detect remarkable peak corresponding to silicon crystal, thus, thinks that these silicon thin films are amorphous or crystallite.

Fig. 7 illustrates the Auger depth section of the silicon thin film (negative active core-shell material film) of example 4.As from understanding Fig. 7, in described silicon thin film forming process, form in the example 4 of layer of aluminum film, at a position sensing to a significant aluminium peak corresponding to described intermediate layer.Example 4 points out, when forming described aluminium film in described silicon thin film forming process, the growth of the silicon grain discontinuous possibility that becomes increases.

Though do not illustrate, even in the process that described silicon thin film (negative active core-shell material film) forms, form in the example 5 of lithium film, with Fig. 7 in identical mode at a position sensing to a lithium peak corresponding to described intermediate layer.Even from example 5, be appreciated that when described lithium film be in the forming process of described silicon thin film, to form, become discontinuous possibility of the growth of silicon grain increases.

When described Auger depth section in the example 4 and the comparison of the Auger depth section in the example 5, the aluminium peak distribution milder (gentle) in the lithium peak distribution proportion 4 in the example 5.Its reason is thought as follows: lithium atom is littler and lighter than aluminium atom, thus the easier dispersion and mobile in the film forming process or after film forms of described lithium atom.

The described lithium rechargeable battery that forms in example 4 and example 5 and the comparative example 2 stands under 20 ℃ the probe temperature, charge/discharge current is 7.5mA/cm ², and the charging scope is that 4.2V tests to the charge/discharge cycle under the condition of 2.5V.The described capacity after 50 circulations and 200 circulations of obtaining is used as battery capacity conservation rate (cycle characteristics) with respect to the ratio of described initial discharge capacity.Table 2 illustrates its result.

Table 2

	Example 4	Example 5	Comparative example 2
	Example 4	Example 5	Comparative example 2	After 50 circulations	????96％	????97％	????76％
After 200 circulations	????82％	????83％	????58％	After 50 circulations	????96％	????97％	????76％

As understanding from table 2, basic in discontinuous example 4 in the center of thickness direction and example 5 being grown on the boundary layer of described silicon grain, described battery capacity conservation rate after 50 circulations and 200 circulate than the battery capacity conservation rate height in the comparative example 2, in described comparative example 2, do not have described intermediate layer, and the gamut that is grown on the thickness direction of described silicon grain is continuous.

And when comparing initial discharge capacity, the initial discharge capacity in the initial discharge capacity fundamental sum comparative example 2 in the example 4 equates, yet the initial discharge capacity in the about ratio 4 of the initial discharge capacity in the example 5 is high by 5%.Its reason supposition is as follows: a part of lithium that constitutes described intermediate layer plays a part to replenish a part of lithium ion, and described lithium ion can not move freely in described silicon thin film after initial charge for some reason.

Thus, make by formation can to obtain the multilayer silicon thin film in described cylindrical particle silicon discontinuous described intermediate layer in described silicon thin film that this silicon thin film comprises the two-layer at least silicon thin film that contains silicon as main component.In using the situation of described multilayer silicon thin film as the described anode active material layer of lithium rechargeable battery, even increase the whole thickness of described anode active material layer, cycle characteristics can not degenerated yet.Thus, the energy device that can provide the raising of a kind of battery capacity and cycle characteristics all to be met.

Embodiment 2

With a kind of energy device of introducing according to the embodiment of the invention 2.

Fig. 8 illustrates the exemplary schematic construction according to the embodiment of the invention 2.The described energy device of present embodiment has cell device 20 and is layered in structure on the substrate 22.In described cell device 20, anode collection sheet 27, positive electrode active materials 26, as nonconducting layer solid electrolyte 25, negative active core-shell material 24, and negative pole currect collecting sheet 23 forms in proper order with this.In Fig. 8, though described substrate 22 is arranged to described anode collection sheet 27 1 sides of described cell device 20, described substrate 22 also can be arranged to described negative pole currect collecting sheet 23 1 sides.

As for described substrate 22, can use such as polyimides (PI), polyamide (PA), poly-to chatting dioctyl phthalate second diester (PEN), polyethylene terephthalate (PET), or the flexible material of other polymer film; The stainless steel metal paper tinsel; The metal forming of nickeliferous, copper, aluminium or other metallic element; Or other material.And, also can use silicon, glass, pottery, plastics of different shape etc., and according to the present invention, the material and the shape of described substrate there is not particular restriction.Only need suitably select the material and the shape of described substrate according to the desirable characteristics of described energy device.

As for described anode collection sheet 27, for example can use, such as the metal of nickel, copper, aluminium, platinum, platinum-palladium, gold, silver, titanium or ITO (tin indium oxide).Depend on the final form of described energy device, described substrate 22 is being arranged into described anode electrode side, and use in the situation of electric conducting material as described substrate 22, described substrate 22 can be used as described anode collection sheet 27, and described like this anode collection sheet 27 just can be removed.

As for described positive electrode active materials 26, for example can use cobalt acid lithium, lithium nickelate, or similar material.The material that is used for positive electrode active materials 26 of the present invention is not limited to above-mentioned material, also can use other material.

As for described solid electrolyte 25, can use material with ionic conductivity and insignificant little electron conduction.Particularly, be under the situation of lithium rechargeable battery at described energy device, because lithium ion is removable ion, because good lithium ion conductive, so preferred by mixing Li ₃PO ₄And nitrogen (or replaces Li with nitrogen ₃PO ₄In an a kind of part of element) or other material and a kind of material of obtaining (LiPON: typical composition is Li _2.9PO _3.3N _0.36).Similarly, by a kind of sulfide, as Li ₂S-SiS ₂, Li ₂S-P ₂S ₅, Li ₂S-B ₂S ₃, it also is effective waiting the solid electrolyte of making.And, by using such as the halide of the lithium of LiI or such as Li ₃PO ₄The lithium oxysalt mix up above-mentioned electrolyte and a kind of solid electrolyte of obtaining also is effective.The material that is used for solid electrolyte 25 of the present invention is not limited to above-mentioned material, and other material also can be used for described solid electrolyte 25.By using a kind of solid electrolyte to be used as electrolyte, no longer need be in the conventional liq electrolyte measure of necessary anti-leak of liquid, this helps the miniaturization of energy device and the reduction of thickness.

As for described negative active core-shell material 24, can use to comprise two-layer at least the silicon thin film that contains silicon as the silicon thin film of main component with sandwich construction.

As for described negative pole currect collecting sheet 23, with described anode collection sheet 27 in identical mode, for example can use, such as the metal of nickel, copper, aluminium, platinum, platinum-palladium, gold, silver or ITO (tin indium oxide).Final form according to described energy device, described substrate 22 is being arranged into described negative electrode side, and use under the situation of a kind of electric conducting material as described substrate 22, described substrate 22 can be used as described negative pole currect collecting sheet 23, and described like this negative pole currect collecting sheet 23 can be removed.

Product form to described energy device does not have particular restriction, and can consider various forms.For example, being shown in described cell device 20 among Fig. 8 is layered in duplexer on the long substrate 22 of described flexibility and can be wound into tabular shown in Fig. 9.In this case, an inner core 31 in the plank frame can be arranged in the interior week of described coiling main body 30.

Figure 10 is the perspective view that is shown in the described tabular energy device among Fig. 9.In Figure 10, Ref. No. 32 and 33 is illustrated in the pair of external electrodes that the two ends of described coiling theme 30 provide.Described outer electrode 32-33 can be made by various conductive materials, as nickel, zinc, tin, scolding tin, electroconductive resin or the like.As for the method that forms described outer electrode 32-33, can use thermal spraying, plating, coating or the like.Described negative pole currect collecting sheet 23 is electrically connected to an outer electrode 32, and described anode collection sheet 27 is electrically connected to another outer electrode 33.In this case, on Width (coiling center position), be used to form a regional formation pattern that needs of described negative pole currect collecting sheet 23 and described anode collection sheet 27 so that pair of external electrodes 32-33 is insulated from each other.

Figure 11 is the viewgraph of cross-section that the another kind of product form of described energy device is shown.In Figure 11, Ref. No. 35 expression pair of external electrodes.Described negative pole currect collecting sheet 23 is electrically connected to an outer electrode 35, and described anode collection sheet 27 is electrically connected to another outer electrode 35.Be used to form the material of described outer electrode 35 and formation material and the method that method is similar to the described outer electrode 32 that is shown in Figure 10.

Ref. No. 36 is illustrated near the in described negative pole currect collecting sheet 23 of the coupling part that is connected to described outer electrode 35, and near the fuse part that in described anode collection sheet 27, provides the coupling part that is connected to described outer electrode 35.Fuse part 36 is used for causing that as safety device fuse blows when overcurrent flows through, thereby cuts off overcurrent, avoids burning thus.In the present embodiment, though in described negative pole currect collecting sheet 23 and described anode collection sheet 27, provide described fuse part 36, provide described fuse part 36 in any one that also can be in them.

Figure 12 A is the plane graph that an example of described fuse part 36 is shown.Figure 12 B is from the observed viewgraph of cross-section of the direction of arrow along the line 12B-12B among Figure 12 A.The width of part that described flow collection sheet 23 and 27 has a pattern respectively so that electric current is flowed through is narrower, forms described fuse part 36 thus.When overcurrent flow through, described fuse part 36 caused that owing to Joule heat produces heat fuse blows, thereby cuts off described overcurrent.Thus, can avoid such as the serious situation of burning.The structure of described fuse part 36 is not limited to the structure shown in Figure 12 A and the 12B.For example, described fuse part 36 can be constructed by the thickness that reduces described negative pole currect collecting sheet 23 and described anode collection sheet 27 partly.Perhaps, described fuse part 36 can form by form dissimilar materials respectively in described negative pole currect collecting sheet 23 and described anode collection sheet 27, and this material has big temperature coefficient of resistance under special pattern.The temperature coefficient of resistance of described different kind of material is greater than the temperature coefficient of resistance of described negative pole currect collecting sheet 23 and described anode collection sheet 27.Therefore, when the temperature of described fuse part 36 slowly increased during in overcurrent, the resistance of described different kind of material increased fast.Therefore, current concentration flows through the material that is used for described negative pole currect collecting sheet 23 and described anode collection sheet 27, rather than flow through in the different kind of material in described fuse part 36, and therefore, because Joule heat, described fuse partly produces heat, causes that fuse blows, thereby cuts off overcurrent.

In Figure 11, Ref. No. 37 expressions provide a protective layer of purposes such as being used for mechanical protection, moisture-resistant enhancing, prevent that the intermediate layer from peeling off.The examples of material that is used for described protective layer 37 includes, but are not limited to, surface treatment reagent, and solid or thermosetting resin, metal, metal oxide, metal nitride as silane coupler, light, or the like.As for the method that is used to form described protective layer 37, can adopt a kind of wet processing such as coating, immersion plating (immersion), spraying etc.; Perhaps a kind of dry process such as vapor deposition, sputter etc.And described protective layer 37 can be made up of the multilayer complex films that different kind of material or same kind material are made.Can on the outer surface of the described energy device except that described outer electrode 35, form described protective layer 37.According to the material that is used for described substrate 22, can not form described protective layer 37 on the surface of described substrate 22, as shown in figure 11.

And described energy device can constitute by repeating the described cell device 20 of stacked requisite number purpose.

Example 6 and example 7, and comparative example 3

With the example of introducing corresponding to embodiment 2.

Respectively by the vacuum vapor deposition, at polyimide film (thickness: 25um) go up stacked nickel (thickness: 0.5um) as described anode collection sheet 27 as described substrate 22, and as the cobalt of described positive electrode active materials 26 acid lithium (thickness: 8um), and, by the solid electrolyte 25 (thickness: 2um) of vacuum vapor deposition stacked lithium phosphate base on described positive electrode active materials 26.

Then, on the surface of described solid electrolyte 25, form silicon thin film (thickness: 5um) as described negative active core-shell material 24.This will be described in detail below.

Then, on the surface of described negative active core-shell material 24, form nickel (thickness: 0.5um), thus, obtain to be shown in the banded duplexer among Fig. 8 with stepped construction as described negative pole currect collecting sheet 23.

The duplexer that obtains like this is wound into tabular, and forms pair of external electrodes 32-33 so that be electrically connected to described anode collection sheet 27 respectively and described negative pole currect collecting sheet 23, obtains the tabular lithium rechargeable battery shown in Figure 10 thus.

Introduce a kind of method that is used to form as the silicon thin film of described negative active core-shell material 24 with reference to Figure 13.

Being shown in the device among Figure 13 and the difference of the device shown in Fig. 1 is, form a vapor deposition source 71 of layout and vapor deposition source, an intermediate layer 75 among the chamber 1c at described film, introduce spout 55 to replace the described first spatter film forming source 52, described gas, and the described second spatter film forming source 52.In Figure 13, represent with identical Ref. No. with the similar elements shown in Fig. 1, and its explanation will be omitted.

Be formed with described anode collection sheet 27, described positive electrode active materials 26 on it, and the described tape substrates 22 of described solid electrolyte 25 is from described unwinding roller 11 unwindings, reel in succession by described conveying roller 12a, described shell roller 13 and described conveying roller 12b transmission, and around described take up roll 14.In this process, such as the particle (hereinafter being called " evaporating particle ") of atom, molecule or the cluster that produces from described vapor deposition source 71 and vapor deposition source, described intermediate layer 75 mask plate 4 by described partition wall 1a, and be adsorbed onto on the surface of the described solid electrolyte 25 of the described substrate 22 of coiling on the described shell roller 13, thereby form described film 6.Arrange that described vapor deposition source 71 and vapor deposition source, described intermediate layer 75 are with relative with described substrate 22.Vapor deposition source, described intermediate layer 75 is placed on the center of the rotation direction of substrate 22 substantially, is in from 71 emissions of described vapor deposition source and the evaporating particle stream by described mask plate 4.Vapor deposition source, described intermediate layer 75 extends across the whole width near the Width (perpendicular to the figure surface direction of Figure 13) of the described substrate 22 the described shell roller 13.Therefore, vapor deposition source, described intermediate layer 75 is as second mask plate, and prevents to be deposited on the zone of outer surface of the described shell roller 13 relative with vapor deposition source, described intermediate layer 75 from the particle of described vapor deposition source 71 evaporations.Therefore, at first, mainly be deposited on from the particle of described vapor deposition source 71 evaporation on the surface of described solid electrolyte 25 of described substrate 22; Then, from vapor deposition source, described intermediate layer the main deposits of particle of 75 evaporations thereon, and the main once more deposit of the particles of 71 evaporations from described vapor deposition source is thereon.

In example 6 and example 7, use said apparatus, respectively by the vacuum vapor deposition, the 71 evaporation silicon from described vapor deposition source, and 75 evaporation a kind of copper-aluminium base materials (fusing point Tm=548 ℃) from vapor deposition source, described intermediate layer, thus, formation has the described negative active core-shell material 24 (gross thickness: 5um) of sandwich construction.

In addition, in the example 6, in the forming process of described negative active core-shell material 24,, make the peripheral surface temperature of described shell roller 13 remain on 20 ℃ by making hot storage medium (not shown) in described shell roller 13 inner loop.

In addition, except the peripheral surface temperature of described shell roller 13 remains in the forming process of described negative active core-shell material 24 280 ℃, example 7 is the same with example 6.

Except only with described vapor deposition source 71, and vapor deposition source, described intermediate layer 75 removed, the peripheral surface temperature of described shell roller 13 remains on 20 ℃ in the forming process of described negative active core-shell material 24, and (thickness: 5um), comparative example 3 is the same with example 6 to form the described negative active core-shell material 24 with single layer structure.

Figure 14 A and 14B schematically illustrate the cross section SEM figure on 24 thickness directions of negative active core-shell material (silicon thin film) described in example 6 and the example 7.In every width of cloth figure, scheme surperficial bottom side corresponding to described solid electrolyte 25 sides, and scheme the surface of surperficial upside corresponding to described negative active core-shell material 24.

(be shown in this order among Figure 14 A and the 14B) in example 6 and the example 7, silicon grain grows into the cylindrical particle that is down frustum-like shape substantially, and described particle diameter increases gradually from the interface between described silicon thin film and the described solid electrolyte 25; Yet the both sides that are grown in layer (intermediate layer) 70 of silicon grain are all discontinuous, and the core of described layer 70 on thickness direction has thickness a little.Described negative active core-shell material 24 is divided by described intermediate layer 70, and has double-layer structure in vertical direction.Described intermediate layer 70 is the copper-aluminium base films that formed by vapor deposition source, described intermediate layer 75.Silicon grain in one deck of described intermediate layer 70 upsides from described intermediate layer 70 beginnings substantially with the growth of falling the frustum-like shape, thereby be suppressed in the increase of the particle diameter of the near surface of described negative active core-shell material (silicon thin film) 24.

In addition, following discovery is arranged.In the described negative active core-shell material 24 (example 6, Figure 14 A) that forms when the peripheral surface temperature of described shell roller 13 is set to 20 ℃, described intermediate layer 70 is continuous films; Yet in the described negative active core-shell material 24 (example 7, Figure 14 B) that forms when the peripheral surface temperature of described shell roller 13 is set to 280 ℃, described intermediate layer 70 is not a continuous film, and is divided into netted or island.Its reason is considered to: the fusing point of described copper-alumina-base material is lower than the fusing point of silicon; Therefore, when described copper-alumina-base material when high temperature forms film, might be divided into netted or island.The division in the described intermediate layer 70 that relatively recognizes by 7 of example 6 and examples is to be confirmed in the situation of being made by copper-alumina-base material in described intermediate layer 70 not only, and also is confirmed in the situation that described intermediate layer 70 is made by another kind of low melting material.

In addition, with example 6 in form described negative active core-shell material 24 under the identical condition after, it is heated to 280 ℃, cooling then, and take the SEM picture of cross section on the thickness direction.Therefore, final intermediate layer with example 7 (Figure 14 B) in described intermediate layer 70 identical modes be divided into netted or island.That is to say, confirmed, form, heat then, also can obtain to be divided into the intermediate layer of netted or island even work as the continuous intermediate coat of making by low melting material.

Though do not illustrate, in the comparative example 3 that does not adopt intermediate layer gaseous sources 75, with with the identical mode of comparative example 2 (Fig. 6 A), silicon grain is grown to the cylindrical particle that is down frustum-like shape basically, and described particle diameter is from increasing gradually at the interface between described silicon thin film and the described solid electrolyte 25, and in the near surface maximum of described negative active core-shell material 24.

The described lithium rechargeable battery that obtains in example 6 and example 7 and comparative example 3 is 3mA/Gm at 20 ℃ probe temperature, charge/discharge current ², to be 4.2V stand the charge/discharge cycle test to the charging scope under the condition of 2.5V.After 50 circulations and 200 circulations, obtain described discharge capacity and be used as battery capacity conservation rate (cycle characteristics) with respect to the ratio of described initial discharge capacity.Table 3 illustrates this result.

Table 3

	Example 6	Example 7	Comparative example 3
	Example 6	Example 7	Comparative example 3	After 50 circulations	????82％	????79％	????54％
After 200 circulations	????67％	????65％	????26％	After 50 circulations	????82％	????79％	????54％

As understanding from table 3, wherein basically on an intermediate layer of the center on the thickness direction, the growth of described silicon grain is in discontinuous example 6 and the example 7, after 50 circulations and 200 circulations, described battery capacity conservation rate is than the battery capacity conservation rate height in the comparative example 3, in described comparative example 3, do not have described intermediate layer, and described silicon grain to be grown in the gamut on the thickness direction be continuous.

In table 3, between example 6 and example 7, do not observe the significant difference of cycle characteristics, the described intermediate layer in the example 6 is a continuous film, and the described intermediate layer in example 7 is the film that is divided.

Carrying out under high charge/discharge-rate of 5C under the situation of charge/discharge, the described capability retention in the example 6 is 58% after 50 circulations, and in the example 7 then is 65%.Therefore, in example 7, obtain good result.Its reason is thought as follows: described intermediate layer is divided into netted or island, and thus, ion is easier moving in described negative active core-shell material 24.

In this example, form described negative active core-shell material 24 with a vapor deposition source 71 with double-layer structure.Yet two the vapor deposition sources as shown in Figure 5 of also can adopting form the described negative active core-shell material 24 with double-layer structure.

In

embodiment

1 and 2, on the surface of described afflux lamella, directly provide described negative active core-shell material film (silicon thin film).Yet the present invention is not limited to this, can provide described negative active core-shell material film by a bottom that is formed on the described flow collection sheet laminar surface.Described bottom is to form in order to strengthen the absorption between described afflux lamella and the described negative active core-shell material film (silicon thin film), antirust processing or the like.Particularly, can use, for example the layer handled of silicon-copper film, chromate etc.Perhaps, can use the layer that forms by surface treatment (back explanation).

In addition, in the foregoing

description

1 and 2, form described negative active core-shell material film (silicon thin film) by sputter or vapor deposition.Yet the present invention is not limited to this.Also can use other vacuum film-forming method such as CVD, even and under these circumstances, also can obtain similar effects.

In addition, the negative active core-shell material film described in the previous example has the double-layer structure of being made up of two-layer silicon thin film.Yet the present invention is not limited to this, also can use three layers or more multi-layered sandwich construction.Because described sandwich construction can obtain the enhancing as the cycle characteristics of effect of the present invention.The thickness of one deck silicon thin film is preferably 12um or thinner, 6um or thinner more preferably, and most preferably be 2um or thinner.When the thickness of one deck silicon thin film surpassed 12um, the particle diameter of the described cylindrical particle in the described silicon thin film increased, and thus, it is remarkable that the reduction of cycle characteristics becomes.Therefore, thickness at one deck silicon thin film surpasses under the situation of 12um, though strengthened cycle characteristics by allowing the negative active core-shell material film to have sandwich construction, but the situation that is not divided into a plurality of layers with described negative active core-shell material film is compared, from the angle of long-time use, still exist problem.The quantity of described negative active core-shell material film can be set according to the thickness of the described negative active core-shell material film that will form.

Because lithium absorption, the representative diameter of the silicon grain that obtains in the example was about 2 to 15um before expanding in the above, and usually, and each silicon grain is that the bond of 1 to 6um silicon fine granular is formed by a plurality of diameters.Should be noted that the silicon grain diameter among the present invention is not limited to this.

The Copper Foil that is used as described negative pole currect collecting sheet in the example 1 to 5 can be accepted surface treatment.As for the surface treatment that is used for described Copper Foil can be: zinc-plated; The alloy plating of zinc and tin, copper, nickel or cobalt; One azole (azole) derivative of use such as BTA forms a cover layer; The solution that use contains chromic acid or bichromate forms a Chromium coating film; Maybe can use the combination of above-mentioned processing.Perhaps, the substrate that also can use another kind to have the copper coating replaces Copper Foil.Can carry out above-mentioned surface treatment at the surface of described copper coating.

Though in the foregoing description and example, do not mention, be in the atmosphere of inert gas or nitrogen, to form under the silicon thin film ideal situation.Can form surface (opening of the described mask plate 4 in the above-mentioned example) towards film and introduce atmosphere gas.Perhaps, can introduce described atmosphere gas to spread all over whole vacuum tank (the described film in the above-mentioned example forms chamber 1c).From the angle of validity, preferably form the surface and introduce described atmosphere gas towards described film.

By in such atmosphere gas, forming silicon thin film, can prevent to gather and grow and increase the situation of silicon grain diameter being parallel to silicon cylindrical particle located adjacent one another on the direction of described film formation surface.Therefore, the degeneration of the described cycle characteristics that causes owing to the excessive expansion/contraction of silicon grain in the charge/discharge process can be suppressed.Experiment according to the present inventor, be omitted though the figure of detailed experimental result is shown, by form silicon thin film in above-mentioned gas atmosphere, the charge/discharge cycles that reduces the battery capacity conservation rate to 80% of this energy device increases, for example, increase 15%-50%.

Preferred gas introducing amount is particularly set according to described thin film deposition speed R (nm/s) according to the film formation condition of described silicon thin film.For example, under the situation that forms introducing gas in surface towards described film, per 100 millimeters films form the gas introducing amount Q (m of width ³/ s) preferably 1 * 10 ^-10* R to 1 * 10 ^-6In the scope of * R, and more preferably 1 * 10 ^-9* R to 1 * 10 ^-7In the scope of * R.When gas introducing amount is too little, then can not obtain above-mentioned effect.On the contrary, when gas introducing amount is too big, the deposition rate of described silicon thin film reduces.

As for the gas that will use, from the angle of the conspicuousness of practicality and above-mentioned effect, argon gas is most preferred.

In addition, a part of silicon that preferably is contained in the described silicon thin film is oxide.The content height of the silicon in described silicon thin film, and under the big situation of battery capacity, the degree of the expansion of described silicon thin film in charge/discharge process may increase, and cycle characteristics may be degenerated.When described silicon thin film contains the oxide of silicon,, can be suppressed in the expansion of silicon thin film described in the charge/discharge process, and can strengthen cycle characteristics because the expansion of the oxide of described silicon in charge/discharge process is less.For example, be preferably formed silicon thin film, 20% of the silicon that is comprised in described silicon thin film becomes oxide to 50%.Experiment according to the present inventor, though the figure of detailed experimental result is shown to be omitted, by allowing described silicon thin film to contain the oxide of silicon, the charge/discharge cycles that reduces the battery capacity conservation rate to 80% of this energy device increases, for example, increase 10%-140% (this depends on described silicon thin film).

For example, by the gas at described film formation near surface introducing oxygen base, and allow described gas and silicon atom to react when silicon thin film forms in vacuum, a part of silicon can form oxide.For intensified response, use ozone, and to wait the mode that energy is provided by plasma, substrate potential energy be effective.

The introducing amount of preferred gas is to set according to the film formation condition of described silicon thin film, particularly, sets according to described thin film deposition speed R (nm/s).For example, under the situation that forms introducing gas in surface towards film, per 100 millimeters films form the gas introducing amount P (m of width ³/ s) preferably 1 * 10 ^-11* R to 1 * 10 ^-5In the scope of * R, more preferably 1 * 10 ^-10* R to 1 * 10 ^-6In the scope of * R, and most preferably 1 * 10 ^-9* R to 1 * 10 ^-7In the scope of * R.Should be noted that according to apparatus-form etc., described gas introducing amount P is not limited to top scope.When described gas introducing amount is too little, then can not obtain above-mentioned effect.On the contrary, when described gas introducing amount is too big, whole silicon thin film will become oxide, and this will reduce battery capacity.

The application of energy device of the present invention does not have particular restriction.For example, described energy device can be as the secondary cell of undersized thin and light portable equipment.

Under the situation that does not break away from spirit of the present invention and substantive characteristics, the present invention can other form implement.Disclosed embodiment should be considered to schematically in all respects in the application's book, and nonrestrictive.Scope of the present invention by appended claims but not aforementioned specification limit, and the institute in claims full scope of equivalents and the meaning change all should be within the scope of the present invention.

Claims

1, a kind of energy device that comprises afflux lamella and negative active core-shell material film, wherein said negative active core-shell material film is direct, or passes through a bottom on described afflux lamella,

Wherein said negative active core-shell material film has the sandwich construction that comprises two-layer at least silicon thin film, and described silicon thin film contains silicon as main component.

2, energy device as claimed in claim 1, wherein said silicon thin film has cylindrical particle, and its thickness direction is its longitudinal direction, and

Described cylindrical particle is discontinuous between described silicon thin film adjacent one another are on the thickness direction.

3, wherein there is a boundary layer in energy device as claimed in claim 1 between described silicon thin film adjacent one another are.

4, wherein there is the compound of silicon and a kind of elemental gas in energy device as claimed in claim 3 in described boundary layer.

5, energy device as claimed in claim 4, wherein said compound are nitride or oxide.

6, energy device as claimed in claim 1, the atomic percentage that wherein has a silicone content between described silicon thin film located adjacent one another is less than 50% intermediate layer.

7, energy device as claimed in claim 6, wherein said intermediate layer contains lithium.

8, energy device as claimed in claim 6, wherein said intermediate layer is a discontinuous film.

9, energy device as claimed in claim 6, wherein said intermediate layer has island.

10, energy device as claimed in claim 6, wherein said intermediate layer contain the low-melting element of fusing point than silicon.

11, energy device as claimed in claim 1, a part of silicon that wherein is included in the described silicon thin film is oxide.

12, a kind of method that is used to make energy device, in described energy device, negative active core-shell material film and positive electrode active materials film said method comprising the steps of by a nonconducting layer toward each other:

By vacuum film-forming method, directly or by a bottom, on an afflux lamella, form described negative active core-shell material film, and form described positive electrode active materials film,

The described step that wherein forms described negative active core-shell material film comprises at least two silicon deposit steps of separating in time.

13, the method for manufacturing energy device as claimed in claim 12, wherein, between described at least two silicon deposit steps, the formed silicon that contains stands surface reformation processing as the surface of the silicon thin film of main component.

14, the method for manufacturing energy device as claimed in claim 13, reforming and handle in wherein said surface is the surface that gas is incorporated into described silicon thin film.

15, the method for manufacturing energy device as claimed in claim 14, wherein said gas contains nitrogen or oxygen is used as main component.

16, the method for manufacturing energy device as claimed in claim 14, wherein said gas is ionized or forms plasma.

17, the method for manufacturing energy device as claimed in claim 12, wherein the atomic percent of silicone content is lower than 50% intermediate layer and forms between described at least two silicon deposit steps.

18, the method for manufacturing energy device as claimed in claim 17, wherein said intermediate layer are and then described silicon deposit steps, form in vacuum environment by vacuum film-forming method.

19, the method for manufacturing energy device as claimed in claim 17, wherein said intermediate layer is by vacuum film-forming method, forms in vacuum environment, succeeded by described silicon deposit step.

20, the method for manufacturing energy device as claimed in claim 17, wherein said intermediate layer contain the low-melting element of fusing point than silicon.

21, the method for manufacturing energy device as claimed in claim 17 supposes that wherein the fusing point of the material that is used to form described intermediate layer is Tm ℃, and the temperature of film formation surface remains on Tm/3 ℃ or higher in the forming process of described intermediate layer.

22, the method for manufacturing energy device as claimed in claim 17, wherein after described intermediate layer formed, described intermediate layer was heated to the temperature that is equal to or higher than its fusing point.

23, the method for manufacturing energy device as claimed in claim 12, wherein said silicon deposit step is to carry out in the environment of inert gas or nitrogen.